The Safety Analysis And Process Improvement On Electrical Arc Burnt Tail Pin

A company is the largest suppliers of related rail products in UK. From2006, TheCompany established offices in China and began to purchase rail products and made effortson localization the British Standard components. In2010, we purchased one batch of tail pinsfrom China and found some arc burnt marking on the top of the head and the end face of tail.According GB/T15822—2005, during the operation of MAGNETIC PARTICLEINSPECTION, care shall be taken to avoid damage to the component of electrical contacts.Possible hazards include excessive heat, burning and arcing. Arcing or excessive heating shallbe regarded as a defect requiring a verdict on acceptability. Tail pin is an importantcomponent for the connecting between draw bar and the train. Mainly tail pin bear the pullforce from shaft and loaded on tail pin loop. If the defects on the surface affect the fatigue lifeof the tail pin, the safety of railway transportation will be threatened.The studies object of this paper is tail pin which have been electrical arc burnt during theoperation of MAGNETIC PARTICLE INSPECTION. Firstly the paper introduces14classifications of coupling systems which the tail pin is assembly and3train accidents whichare caused by the failure of critical components. The paper will analyze the reasons to causethe arc burnt from the theory of MAGNETIC PARTICLE INSPECTION. After that paper willanalyze the affection of arc burnt on the safety by a series tests on the failure tail pin. The testsare including Macro morphology-analysis, micro-analysis, energy spectrum analysis,chemical composition analysis, and mechanics performance testing, metallographic analysisand CATIA finite element analysis. The final of the paper will provide some suggestions toimprove the manufacturing process of tail pin.From the test results, we could found that the position of the arc burnt is not the criticalareas for the tail pin. The critical areas are faces which is perpendicular to the pin axial andthe rod and ring transition. Because the mechanical performance could not meet therequirements of material standard, the tail pin could be crack when the trains are overloadedor suffer a larger than recently experienced tensile load.There are seldom researches for the affection of arc burnt to the tail pin’s safety. Thispaper could be an example for the arc burnt research. Research of reliability of tail pin is asystems engineering and expect there is a further discussion and research in the future.